." >> from the senate floor, nevada's harry reid said marines all over the world are mourning the loss. >> "my thoughts are with those who were injured and of course the >> the accident happened late monday night. emergency officials say four medical helicopters were sent to transport patients to area hospitals. the white house says president obama was immediately briefed on the incident. >> "the president's thoughts and prayers go to the families of those who were lost and to those who are injured. we're obviously in the early stages of assessing the incident. it's a tragedy, clearly." >> the army depot is used for storing ammunition and weapon stocks set to be deactivated. it's also used by military units for high desert trainingfore deployment overseas. the marines involved were based at camp lejeune, n.c. while the investigation continues, the military is holding off on using any of the mortars from the same manufacturing lot as the ones that were used at the nevada base. >> catherine: while not unexpected, a huge blow today for advocates of gun control. senate majority leader harr